Electrophysiology/Cell Culture Core is designed to provide PPG investigators with an array of commonly[unreadable] utilized cultured human intestinal epithelial cell lines (Caco-2, T84, HT-29, and NCM460) and access to a[unreadable] multitude of electrophysiological measurements on both cultured epithelial sheets and native tissues. Both[unreadable] Core components house state-of-the-art equipment, which is run by personnel with full technical expertise so[unreadable] that training, assistance with experimental design, data collection, data analysis and interpretation are[unreadable] provided. This Core is under dual direction by Drs. Gail Hecht and Mrinalini Rao. They both have extensive[unreadable] experience in all aspects of electrophysiological measurements in cultured intestinal epithelia, native intestinal[unreadable] tissue, and primary intestinal cells. The Specific Aims are to provide the investigators and projects within this[unreadable] Program Project with human cultured intestinal epithelial cells including Caco-2, T84, HT-29, and NCM460[unreadable] grown on plastic or permeable (Transwell) filters; electrophysiological measurements in Ussing chambers[unreadable] including short circuit current (Isc), transepithelial electrical resistance (TER), ion flux analysis, on both[unreadable] cultured intestinal sheets and native intestinal tissues; and spectrofluorometric measurements as a[unreadable] complementary approach to assessing ion transport. The provision of these cells for electrophysiologic[unreadable] measurements will facilitate and expedite the proposed experiments of all of the Program investigators and[unreadable] will standardize the conditions under which these cells are grown thus allowing for direct correlation of data[unreadable] obtained for each of the Projects.